Embedded Linux

[fk5747]

hi everybody

I am getting started with linux driver development and I want to test how to insert a driver into linux kernel. I've built and run the linux kernel on MicroBlaze on my custom spartan3e board and every thing works fine.

my driver is so simple :

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>

MODULE_LICENSE("BSD/GPL");
static int hello_init(void) {
  printk("KERN_INFO "Hello : init is working good!");
  return 0;
}

static void hello_exit(void) {
  printk("<KERN_INFO "Hello : exit is working good!");
}

module_init(hello_init);
module_exit(hello_exit);

after compiling the driver I insert it using insmod and it works fine. but then  I cannot remove it

# rmmod hello                                                                   
rmmod: chdir(/lib/modules): No such file or directory 

Am I using rmmod correctly?

I would appreciate any suggestions. thanks in advance.

[fk5747]

hi everybody

I am getting started with linux driver development and I want to test how to insert a driver into linux kernel. I've built and run the linux kernel on MicroBlaze on my custom spartan3e board and every thing works fine.

my driver is so simple :

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>

MODULE_LICENSE("BSD/GPL");
static int hello_init(void) {
  printk("KERN_INFO "Hello : init is working good!");
  return 0;
}

static void hello_exit(void) {
  printk("<KERN_INFO "Hello : exit is working good!");
}

module_init(hello_init);
module_exit(hello_exit);

after compiling the driver I insert it using insmod and it works fine. but then  I cannot remove it

# rmmod hello                                                                   
rmmod: chdir(/lib/modules): No such file or directory 

Am I using rmmod correctly?

I would appreciate any suggestions. thanks in advance.

[madhuba]

Please do "lsmod" to check if the module was really inserted or not.

Regards

Madhubala

[fk5747]

yes, it has inserted correctly! it allocates major and minor numbers too! 

now, what else?

[madhuba · Accepted solution]

Hi ,

The solution to this problem is please create the directory /lib/modules and then /lib/modules/2.6.39

rmmod is looking for this and since its not finding its throwing the error.

Regards

Madhubala

[fk5747]

thank you

It works :)))